Can anyone help me with the math for an express port randomizer

Question

My bot has been corrupting data and randomly crashing and found the problem, it was this bit of code:

Math.floor(Math.random()*6000)

Can anyone help me with this? Also, here is my entire express.js file:

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => {
  res.send('DSB is online')
})

app.listen(port, () => {
  console.log(`BOT listening at http://localhost:${port}`)
})

It says 3000 because that's the original one. I've changed it and that's almost what it says.

Answer 1

You can change the random number to have a minimum value. As CertainPerformance mentioned in their comment it's a good idea to start at 1000 (or maybe 1024) and not zero. Your current code will return with a number between 0 and 6000 (inclusive of 0 but not 6000).

The following function will generate a random integer between a min and max value.

function randomInt(min = 1024, max = 6000) {
  if (min > max) {
    [min, max] = [max, min]
  }
  return Math.floor((Math.random() * ((max - min) + 1)) + min)
}

randomInt() // => 5302

And you can use it like this:

app.get('/', (req, res) => {
  res.send('DSB is online')
})

const server = app.listen(randomInt(), () => {
  console.log(`BOT listening on port ${server.address().port}`)
  // => BOT listening on port 5981
})

In Express, if you want to randomly assign a port, you can simply listen on port 0 :

app.get('/', (req, res) => {
  res.send('DSB is online')
})

const server = app.listen(0, () => {
  console.log(`BOT listening on port ${server.address().port}`)
  // => BOT listening on port 58319
});